Electric starter for automobile-engines.



I A. W. SMHH.

I ELECTHC SIARTER FOR AUTOMOBILE ENGINES.

APPLICATION FILED JUNEZ. \9|4'.

l,144,438. Patented J urne 29, 1915.

1 q object 1s to produce a cheap, simple and d1- 'rect acting' starter.'

f 4 UNITED. sTATEs IPATENT oEEIcE.

ALBERT w. SMITH, or l'WASIIINeToN, nIsTEIcT or COLUMBIA.

. an overrunning clutch, etc.

'provements in Electric Starters for Automobile-Engines, and the following is a specication thereof. l

My invention-relates to an'electric starting system for automobile engines, and 'its Present systems are costlybecause of the expensive motor construction used, comprising .a laminated core, a lspecial field .magnet `and coils, and a special large commutator, to obtain'loWl brush contact resistance; also because of the complicated gearing emplayed, consisting either of a sliding pinion engaging with a ring gear on the Hy Wheel, or of a gear lor chain drive acting through To avoid the use of a sliding pinion, or a clutch mechanism, or both, I'employ a motor that is movable to and from the engine Hy j-wheel, and has a rolling driver acting directly on the Hy wheel. The rolling driver is preferably made vof hardened-steel, andof the driver. The motor also has auxiliary magnet poles conforming to the Hy wheel,v`

which, act when' the motor is energized, -to pull it toward theV Hy wheel, and t-hjfegl' driver into .contact therewith; .when the motorie y v tact therewith. To obtain a cheap and simplestarting" motor, I employ an, unlaminated. ring core,

not energized, a spring acts to-retain itaway from the Hywhee and the driver out cunwound' with square Efcopper wire, bared to form a commutating o1' brush contact surface for the armature. Instead of the usual field magnet, I employ a pole frame without Held coils, having poles conforming to the armature; and also poles conforming to the Hy wheel'. When a currentisv sent through the armature, by means of. brushes having a lead inthe direction of rotation, Held poles are formed in the pole frame by the armature, which then develops a torquerexactly as inthe Aordinary motor'. As the starter is .used for only a second-or two at a timetlere is no appreciable heating, andthe -slig .tt-lessi entailed by the use 'of a solid core Specification of Letters Patent.

ture shaft 11 f b ELECTRIC `S'll'AlltlEIR, FOR AUTOMOBILE-ENGINES.

Patented June 29', 1915.

Application mea :une ze, 1914. serial No'. 847,531.

pensated by the absence of stray Held or magnetic leakage between pole tips, which occurs when a wound field magnet is used.

With the'new driving gear employed by me a high gear ratio, and consequently a high motor speed, can be used. -The use of the armature surface for \commutation enables the employment of very large brushes with light pressure, and insures a low brush friction and contact resistance, which lis of great importance in a'low voltage starter.

The drawings show an end view in Figure l, a side view in Fig. 2, sectional views in Figs. 3 and 4, a modification in Fig. 5 and `detail views in Figs. 6 and 7 1 is the Hy wheel mounted on the crank shaft 2, whichis journaled in the crank case 3.

The pole frame of the. starter consists of poles 6 and 7, and the connecting bridge 8 The armature of the starter consists of the bare faced Winding 9 and the unlaminated ring core 10,.Iand is mounted on the armay means of the spider 12. The rollingdriver of the starter consists of the toothed roll.13 formed integrallytwith x has nurling teeth formed thereon,l and the Hy'wheel has depressions knurled thereon lcorresponding to and meshing with the teeth the hugging-magnet for-the starter, actin to force the driver 13 against the Hy wh'ee 1x l -'.lhebore 17. is machined to receive the i bearings 14 and-15, whichare secured thereini asivshown in Fig. 3. The pole pieces 4 and 5 are bored to receive the armature, and the pole pieces 6' and 7 are machined to conform to the Hy wheel 1.v When theY starter is v,energized the bridge 8 first becomes saturated, after which the magnetic 4vHuit Y is forced through the Hy wheel 1, the thickness i.

of the bridge 8 thus determines the Huxerted on the driver 13.

`The construction of the armatureisy shownthrongh the Hy wheel, and the pressure ex iFigs.- 3 and 4. The winding 9'is''formed of square wire tightlycoiled onto the core 10, and4 its ends soldered together. The spider 12 is thenfinserted `as shown in Figiing compound; and balied-Jter which 11o 3; thev Winding isthen 'soaked with insulat- 'entire outer surface is bared of insulation plied to the armature by the brushes 18 and 19, supported by the insulated brush holders 20 and 21, which are secured to the pole pieces 4 and 5.

The circuit terminals are bolted to the brush holders at'22 and 23. The large commutating face of the armature enables the use oflarge carbon brushes with a light bearing pressure on the amature; thus ob' y taining the low brush contact resistance rer quired by the low voltage current supply of the starter.

The direction of rotation is determined by a forward lead of the brushes, and is indicated by the arrow in Fig. 1. As the starter is magnetized solely by the armature current,

its poles'tend strongly to form in line with the brushes and to cause sparking. To prevent sparking I employ theA unlaminated core 10, in which eddy currents are generated which .cause a lag in the magnetism of the core, and thus act to shift the poles from the brush diameter forward to a position under the pole pieces 4 and 5. Sparking is also minimized by the fact that only a single turn of the winding is commutated at a time. The use of a solid core is not objectionable in a starter, as due toits intermittent use only slight heating is caused by the eddy currents in the core, and the energy loss due thereto is negligible. As the magnetic field of the starter is developed in and by the armature itself, magnetic leakagel cannot oci our; and, if worked below saturation, its

torque will be directly proportional to thecurrent, thus giving the starter the true series motor characteristics required -for en gine starting. The driver 13 and shaft 11, a detail view of which is shown in Fig. 6, are formed of a single piece of tool steel and hardened..

The driver 13-has helical teeth of V-shape milledrthereon, as shown in Figs. 3 and 6 at 24. The teeth24 engage with corres onding depressions25 on the Hy wheel 1. he depressions 25 are formed by means of a nurling tool and are made only deep enough to enable the teeth 24 to exert a positive driving action on the-Hy wheel 1. The use Vof the depressions 25 also hasthe advantage over a smooth Wheel surfacethat less pressure is required on the driver 13, but their use is not essential to the operation of the driver, which will operate on thev smooth surface of the Hy wheel, and can be so employed Whenthe starter is applied to an engine already in use. When the starter is applied -tol an engine wlth a smooth Hy l65 wheel, the driver teeth 24 are made quite Aspring 26.

.and at the same time forces the against the Hy wheel 1 by means of magnetic attraction between it and the poles 6v 13 and. enabling it to form-a nurling 25 on, the Hy wheel. After a period of 4use the teeth 24 lose their keenness and their nurling action then ceases. The object in using helical teeth 24 is to obtain a uniform and smooth driving action of the teeth, and also to produce an end thrust in the shaft 11 to oppose the end pull between the armature and pole frame. The driver 13 can also be used with a smooth face, as shown in Fig. 5,

.but the pressure on the driver must then be' greatly increased. 1

The driver 13 projects slightly beyond the face of the poles 6 and 7, so that when the driver is in contact with the Hy wheel the poles will clear the same by a small amount. When the starter is idle 'the driver 13 is held just clear of the Hy wheel by means of the spring 26 acting to engage the notch 27 with the retaining pin 28, as'shown in Figs. 2 and 7. A

The starter can be applied to either side or to the top of the Hy wheel, as desired or most convenient. In Figs. 1 and 2 the starter is shown as applied to the Hy wheel on the valve side of the engine. This is a good location for the starter when the Hy wheelis exposed. When, however, the Hy wheel is inclosed by a casing 29, as shown in Fig. 5, I prefer to apply the starter to the top of the Hy wheel as shown. The starter is then hinged to the casing 29 at 30, and is supported at its free end bythe compression When it current is sent through the starterpfrom a magneticl Hux which completes its circuit through the bridge 8 and the Hyfwheel 1.

is desired'to start the engine, s

105 batteryfthus developing in the core 10 ay The starterthen produces'a drivin torque,

river 13 and 7. The engine is then driven by the starter at the required starting speed untilstarted, when the battery current is cut off and the starter resumes its idle position by the action of the spring 26.

Having explained my invention in detail, I will now point out some of its advantages.

Great simplicity, cheapness 'of construc tion, and directness .of operation aremadev possible by the employment of the self commutating -and self magnetizing armature and the self engaging driver for the starter.

The use of the armature face for commutation saves the cost of a special ccmmutator and enables the use of large carbon brushes with a low contact resistance, thus removingall objections to a six volt current supply ffor the starter.` The useof the armaturel current for magnetizing the starter rprecludes magnetic leakage and faulty operation due thereto. rlhe use of rolling'gearing requires no overrunning clutch devices, and provides a direct, positive and reliable drive with a high gear ratio of from twenty or thirtyto one for the starter.

Another valuable feature of the starter is its great'compactness, and the fact that it can be applied directly to the Hy wheelfwithout in any way interfering with or crowding the other equipment of the engine.

While the starter is especially adapted for automobile. use, it can also be applied to stationary -engines and to any other types of machinery requiring auxiliary starting.

aving now fully described my invention, I desire to state that the saine is not limited to the eXact construction and relation of elements shown, as these can be modified and combined in other ways without departing from the essential. features of the invention.

What I claim as my invention is:

1. The combination with va Hy wheel of a non-self-starting engine, of an electric start-l ing motor, movably mounted with relation to`said Hy wheel, and having'a rolling driver in operative relation therewith; a spring acting to retain said motor, when unenergized, away from said fly wheel, and said driver out of contact therewith; and auX- iliary pole pieces for said motor, forming a part of the magnetic Held circuit thereof, said pole pieces conforming to said Hy Wheel, and'acting to pull said motor toward said Hy wheel, and vto force said driver into contact therewith, when the motor is energized for starting the engine.

2. The combination with the Hy wheel of a non-self-starting engine, of an electric starting motor, movably mounted with; relation to said fly wheel, and having a rolling driver of hardened steel in operative relation therewith, said driver having nurling teeth or projections formed thereon; a springacting to retain sald motor, when unenerglzed,

away `from said Hy wheel, and said driver out of contact therewith; and auxiliary pole pieces for said motor, forming a part` of `the magnetic field circuit thereof, said pole pieces yconforming to said Hy Wheel, and acting to pull said motor toward said Hy wheel, and to force said driver into con tact therewith, when the motor is enerwheel, and said driver out of contact therewith; and auxiliary pole pieces for said motor, forming a part of the magnetic Held circuit thereof, said pole pieces conforming to said Hy wheel, and acting to pull said m0- tor toward said Hy wheel, and to force said driver into contact therewith, whenthe motor 1s energized for starting the engine.

4. In an electric starting motor for nonframe without HeldV windings, having armature poles, and also poles conforming to the Hy wheel of the engine; a self magnetizing ring armature' mounted on a shaft journaled in said pole frame, a. driving'element on said shaft in operative relation with said Hy wheel; a self commutating lwinding for said armature,` formed of square wire with a bared contact or brush surface, and contact brushes having a lead in the direction of rotation, and bearingdirectly on said winding.

5. In an electric starting motor for nonself-starting engines, in combination, a pole frame withdut field windings, having armature poles, and also poles conforming to .75 self-starting engines, in combination, a pole the Hy wheel of the engine; a self magnet izing ring armature with an unlaminated core, mounted on a shaft journaled in said pole frame, a driving element on said shaft in operative relation with said Hy wheel; a self commutating winding for said armaf ture, formed of square wire with a bared contact or brush surface, and contact brushes and bearing directly on said winding.

. ALBERT W. SMITH. Witnesses:

Rofr. T. PLA'I'r, FRED. A. SCHMIDT.

100. .having a lead in the direction of rotation, 

